Magnetic and resonator selector for carrier conveyers



March 14, 1939. wfHARsREAvEs 2,150,440

MAGNETIC AND RESONATOR SELECTOR FOR CARRIER CONVEYERS Filed June 10,1936 2 SheetS Sheet 1 March 14, 1939. w. HARGREAVES 2,150,440

MAGNETIC AND RESONATOR SELECTOR FOR CARRIER CONVEYERS Filed June 10,1936 2 Sheets-Sheet 2 INVENTOR 4 W. HARGREAVES TORNEY Patented Mar. 14,1939 UNITED STATES PATENT OFFICE MAGNETIC AND RESONATOR SELECTOR FORCARRIER CONVEYERS Application June 10, 1936, Serial No. 84,559

Claims.

This invention relates, in general, to carrier dispatch systemsemploying guideways having one or more branches or points therealong atwhich the carriers are diverted or discharged, and has particularreference to a system in which means is provided for selectivelydiverting or discharging the carriers.

One of the principal objects of this invention is to provide a carrierselector system in which the carriers embody means cooperating with theselecting mechanism for indicating and producing the selective responsedesired in accordance with the predetermined destination of the carrier.

Another object is to provide carriers, to be employed with the selectorsystem, possessing distinctive physical and electrical characteristicswhich will cooperate with the selector device to select or reject thecarriers.

It is another object of this invention to provide a selective carrierswitching apparatus which may be utilized in, or adapted to, presentcarrier installations with but a minimum alteration of the latter, andwithout impairing the usefulness, or materially affecting the capacityor efficiency of the same.

A further object is to provide a carrier selector system of sturdy andinexpensive construction, which will be non-critical to slightdisturbances of the apparatus during operation.

Still another object is to provide a carrier selector system responsiveto the momentary presence of a rapidly travelling carrier and embodyingmeans for prolonging said response a predetermined interval, and forvarying said interval as desired in order to allow sufiicient time forthe carrier to traverse the intervening space between the pick-up orselector and the switching mechanism.

A still further object is to provide a magneticfield selector systemresponsive to carriers having predetermined magnetic properties, whichresponse may be utilized to initiate the operation of suitable dischargeor switching means.

Another object is to provide a novel resonator selector system notrequiring the use of a grid controlled rectifier, and embodying anoscillator pick-up responsive to carriers having predeterminedelectro-conductive properties.

A further object is to provide a carrier system having a plurality ofdischarge or switching points intermediate its ends, and selector meansat each of said intermediate points responsive to certain predeterminedcarriers to cause selective discharge of the same, and non-responsive toall other carriers, so as to permit their uninterrupted passage alongthe carrier guideway.

These and other objects are effected by this invention, as will beapparent from the following description and claims taken in connectionwith the accompanying drawings forming a part of this application, inwhich:

Fig. 1 is a diagrammatic illustration showing a magnetic pick-updisposed in advance of a carrier discharge point, and the necessaryselector circuit for causing selection or rejection;

Fig. 2 is a modified form of Fig. 1 employing an oscillator pick-up anda capacity coupling selector;

Fig. 3 is an illustration of one type of carrier adapted to be used withthe present invention and embodying both magnetic and conductiveproperties; and

Fig. 4 is a diagrammatic view of a carrier conveyer line having aplurality of discharge points embodying the magnetic and oscillatorpick-up and a combination thereof for effecting selective discharge ofthe carriers at their predetermined destination.

Fig. 51s a sectional view of the carrier conveyer line taken on the line55 of Fig. 1 which shows the disposition of the magnetic pickup in itsrelation to the opposite sides of the conveyer tube.

Carrier conveyer lines of the pneumatic type herein described are quiteextensively used for conveying material between various points in alarge building, and even between two or more separate buildingsremotely'situated, and their usefulness and adaptability is greatlyincreased where a system of selective routing and discharge is employed.Such systems make it possible to provide a conveyer line extendingbetween two remote points and having one or more intermediate branchlines or discharge stations therebetween. In this way a main line may beused to serve a plurality of intermediate points from a single sendingstation so as to eiiect an economy in construction costs and maintenanceover a system in which separate lines must be used from the sendingstation to the various remote receiving stations.

Various methods have heretofore been employed for accomplishingselective discharge of the canriers, most of which entail a considerabledeparture in design over installations where only one remote point is tobe served, thus necessitating a substantial expenditure in labor andmaterials for putting in new installations or for converting thosealready in operation.

Hence, I have provided a novel method of selective discharge which willbe economical to install and operate and which will be suitable foradaptation to present installations.

According to my invention, I provide a carrier conveyer line having oneor more transfer Junctures or discharge points intermediate the centralsending station and the remote or end station on the conveyer line.Selective transfer or discharge of the carriers is effected by means ofa switching mechanism disposed at the juncture and operated by anelectrical relay. This relay is selectively controlled by means adaptedto impress a potential thereon whenever a carrier having predeterminedphysical properties passes a predetermined point along the guideway.This point is located in advance of the juncture point and issuificiently spaced therefrom to allow ample time for the properfunctioning of the selector and switching mechanisms.

It has been found desirable to provide means for prolonging the responseof the selector mechanism to the carrier, sufliciently to permit thecarrier to traverse the intervening space between the selector pick-upand the juncture point associated therewith, so that the switch willremain in its desired position long enough to select or reject thecarrier. This is accomplished, as will hereinafter be more fullydescribed, by providing a suitable condenser and variable resistanceshunt in the selector circuit instead of the usual mechanical timer.

Selection of the carriers according to their predetermined destinationis accomplished by providing pick-up devices disposed along the carrierguideway in advance of each intermediate station or branch juncturewhich will respond to certain predetermined physical properties of thecarriers.

In one of the embodiments of this invention I provide a magnetic pick-updevice which will respond only to carriers having predetermined mag--netic properties.

Another embodiment comprises a resonator pick-up or oscillation circuitresponsive only to carriers having predetermined electro-conductiveproperties.

Still another embodiment is obtained by combining the magnetic pick-upwith the resonator pick-up to form a selector unit responsive tocarriers embodying a combination of magnetic and electro-conductiveproperties.

By employing a combination of these various embodiments a branch lineconveyer may be constructed having a plurality of switching points, eachhaving one of the aforementioned embodiments. In this way carriers maybe sent to intermediate stations in accordance with their physicalcharacteristics.

Mmetic selector Referring now to the drawings, Fig. 1 shows a section ofa pneumatic tube carrier conveyer system including a guideway l2, brokenaway at lit to show a carrier l4 travelling therein in the directionindicated by the arrow, a juncture point l5, and an outlet station IS. Apick-up device I! is spaced a short distance in advance of the juncturepoint IS. The pick-up comprises a permanent horseshoe magnet i8 disposedwith the pole pieces on opposite sides of the track tube (see Fig. 5) sothat the latter passes through the field of the magnet in a manner tocut the maximum lines of force.

The magnet i8 is provided with an induction pick-up coil is in whichcurrents may be induced by carriers passing through the guideway 12. The

control mechanism for the pick-up is shown at 20. The winding of thepickup coil is connected between the grid 2i and the cathode 22 of an amplifier (electronic discharge) tube 22.

Theplate circuit of this tube is supplied with a suitable potential froma local source 24. The positive lead 26 connects to the plate 25 andincludes a load resistor 21. The cathode 22 of the amplifier tube 23 isconnected to the negative lead When carriers having a constructionembodying a magnetic substance, preferably in the form of a ring orcollar, pass through the magnetic field between the pole pieces ll ofthe pick-up magnet II, the field is momentarily strengthened and avoltage is induced in the winding l9. This causes current to flow in thegrid circuit. This current, passing through resistor 3!, makes the grid2| of the amplifier tube 23 negative with respect to the cathode 22.

With the carrier travelling at high speed the effect of the metallicportion on the pick-up magnet is in the nature of a short impulse. Theduration of this impulse is ordinarily insufllcient to cause the properfunctioning of the selecting and switching mechanism. To prolong thisresponse, a timing condenser 29 is employed in the grid circuit having avariable resistance shunt 3| so that, when the single impulse passesthrough, it will charge the condenser. By this means the potential inthe grid circuit is maintained despite the discontinuance of theinitiating force and the charge is permitted to slowly dissipate throughthe resistance. By varying the value of the resistor and condenser thelength of time required to dissipate the charge may be varied and thetime during which the switching operation takes place may be controlled.

With this type of timing device, a fixed maximum prolongation of theselection impulse is maintained in the selector mechanism on allselections even though a subsequent impulse is received before theprevious charge has become dissipated. The new impulse serves toreplenish the dissipated energy and restore the charge to maximum sothat the last carrier will have sufilcient time to reach the switchingpoint. The advantage of using this method of timing is that where aplurality of carriers are to be sent from the home station destined forthe same branch etation, they may all be inserted successively in theguideway without regard to spacing.

The plate 25 of the amplifier tube 21 is also connected to the grid 32of a second amplifier tube 33. The cathode 34 of this tube is suppliedwith an operating potential from the movable contact 35 of a voltagedivider 35 connected between the power leads 24. In circuit with theplate 31 of the tube is a relay 38 having a normally open armature 39and a front contact 4|. The armature 39 is connected in circuit with therelay and both are supplied with current from the source 24 by means ofconductor 42. The front contact H is connected by conductor 43 to aswitching solenoid 44 disposed adjacent the juncture l5 of the tubeguideway. A connecting arm 45 joins the moving plunger 46 of thesolenoid to the switch plate 41 pivoted at 48.

Normally the amplifier tube 23 is operating with zero grid bias and thecircuit is adjusted, by means of the voltage divider 35 and the resistor21, so that amplifier tube 33 will have no current flow in its platecircuit, which includes the relay 3B.

Irrespective of the manner in which the winding of the pick-up magnet I1is connected in the grid circuit of tube 23 the induced current.impulsewhich is permitted to flow in the grid circuit by the unilateralconductivity of tube 23 results in a negative bias on the grid 2|. Thiscauses a decrease in the plate current of tube 23 and a consequentincrease in plate potential. Since the grid of tube 33 is connected tothe plate of tube 23, when plate 25 becomes more positive, the potentialof the grid 32 of amplifier tube 38 becomes more positive or, in otherwords, has its negative bias decreased. This causes current to flow inthe plate circuit of tube 33 and the relay 88 becomes energized. Thearmature 38 is then drawn against its front contact 4| and current isthereby supplied to the solenoid H. The energization oi the solenoidoperates the switching mechanism and causes the carrier to be deflectedfrom the main guideway I! to the outlet branch l6.

Resonator selector Referring now to Fig. 2, a modification of theselector control mechanism is shown. The unit illustrated comprises anoscillation generator 50 adapted to be responsive to carriers havingpredetermined metallic properties.

' In a copending application, Ser. No. 10,734, flied March 12, 1935, byAdam Drenkard, Jr.', this type of oscillator pick-up is fully described.

Briefly, the oscillator pick-up comprises a three-element tube 5|provided with a cathode 52, a grid 53 and an anode 54. A tunedinductance or coil 55 is placed inthe grid circuit, and a feed-back coil'56 in the anode circuit inductively coupled to the grid circuit. Inseries with the feed-back coil 56 is a pick-up coil il the latter beingdisposed around a portion of the conveyer tube 12 in advance oi. theswitching point It. The pick-up coil comprises preferably a singlehelical layer wound about a non-metallic portion 58 01 the tube [2. Thenon-metallic portion is suitably insulated from the main carrierguideway as shown at 59.

The circuit is adjusted so that it is normally just below theoscillating point and arranged so that a carrier having predeterminedmetallic characteristics will, in passing through the pickup coil 51,bring the circuit into resonance. A grid leak is provided comprising a.resistance 6| shunted by a condenser 62 so that the tube 5| willnormally pass its minimum current; that is, when the circuit is not inoscillation.

The anode circuit or tube 5| includes the primary of a transformer 63.The high frequencies are filtered out of the circuit by means of thewell known arrangement of a choke coil 84 and condenser 65.

The secondary of the transformer 63 is connected in the grid circuit ofa second three-element tube 66 comprising a grid 61, a cathode 68 and ananode 69. This tube is preferably of a type having a relatively highcathode to grid conductance. The well known type #53 tube has been foundvery suitable although any other make possessing the samecharacteristics may be used.

The grid circuit of tube 66 is provided with a variable resistor Hshunted by a condenser 12, the purpose of which is to prolong theresponse of the tube to the momentary presence of a. metallic carrier inthe pick-up coil so that suflicient time will be allowed for the carrierto traverse the distance between the pick-up coil and the switchingpoint before the circuit returns to normal.

This arrangement provides a simple, inexpensive, and efllcient means fortiming the switching operation where varying local conditions make itnecessary to have a non-uniform spacing between selector unit andswitching point.

In series with the anode circuit of the tube 66 is included the windingof a relay I3. An armature I4 is responsive to the relay and serves topply a source of potential through its back contact IE to the solenoidH.

The tube 68 is normally operated at zero grid bias and is adjusted sothat current will normally flow in the plate circuit. This causes therelay 13 to be normally energized and the armature I4 consequently heldaway from its back contact 15 so that no current is supplied to thesolenoid 44.

When a carrier having predetermined metallic properties, such as anall-metal body, or a metallic conductive surface coating, or metallicband or collar, passes through thepick-up coil, it will increase thecapacitative coupling between the turns of the coil 51. The presence ofa metallic body within the envelope oi the coil causes a change in theamount of current passed through the plate circuit of the tube 5|.

The effect is to cause a material decrease of the current in the platecircuit of the oscillator. This sudden change causes a current pulse tobe passed through the primary oi the transformer 63. A voltage isthereby simultaneously induced in the secondary of the transformer,which voltage causes current to flow in the grid circuit of tube 68. Thepassage of this current through the variable resistor 'Il charges thecondenser 12 and impresses a negative bias on the grid 81.

The current in the plate circuit now drops to zero and the resultingdeenergization of the relay 13 causes the armature 14 to be released anddrawn against its back contact 15. This in turn operates the solenoid IIto eflect the switching operation. The charge in the condenser 12 isdissipated slowly through the resistor I I shunted across it until thecurrent in the plate circuit is built up suificiently to operate therelay l3 and remove the current source from the solenoid 44.

-By varying the value of this resistor, the time during which the relayI3 is deenergized and the switch plate 41 held in its discharge positionmay be controlled.

Fig. 3 shows a type of carrier proposed to be employed in the carrierconveyer system herein described. As stated, it is one of the objects ofthis invention to provide a system embodying a minimum of departure frompresent design and equipment so that the selector pick up devices andcarriers cooperating therewith may be easily placed in presentinstallations. To that end I provide a carrier H of conventional design,and made in substantially the same dimensions as carriers now employedin the systems which do not have selective discharge,

The carrier illustrated is of a type that embodies characteristics thatwill produce a response in both the magnetic pick-up shown in Fig. 1 andthe resonator pick-up shown in Fig. 2. That is it comprises portions ofboth magnetic and electro-conductive material. It is obvious that eitherof these portions may be eliminated to provide a carrier that will causeonly one of the aforementioned selector devices to operate. Asillustrated, the carrier embodies a main body portion 18 ofelectro-conductive non-magnetic material which may be in the form of anall-metal body or a fibre body having a light coating of metal foil. Thehead of the carrier is provided with the usual buffer member 11 offibrous material. Adjacent the buffer member ll is placed a narrowcollar 18 of magnetic material suilicient in size to produce thenecessary response in the magnetic pickp.

Referring now to Fig. 4, I have shown a section of a carrier conveyerline having three branch or juncture points intermediate the sendingstation and the remote receiving station.

At each of the juncture points, designated A, B and C, respectively, aselector pick-up is provided so that predetermined carriers designatedfor a particular station will be selectively discharged thereat and allcarriers not so designated will be rejected to continue theiruninterrupted passage along the main guideway II.

The selector devices are illustrated diagrammatically and only theoperating solenoid N of the switching apparatus at each juncture isshown.

At stationA, the selector mechanism comprises a combination oi theresonator pick-up 50 and the magnetic pick-up 10. The resonator pick-upcoil 51 is disposed in advance of the pick-up magnet II. The controlrelays i3 and 3! of the selector devices have their armatures H and llrespectively connected together. The back contact 15 of the relay 13serves as a current supply for both armatures. The front contact ll ofrelay 3B is in circuit with the switching solenoid N. The operation ofthe mechanism is as follows.

Suppose a carrier, of the type illustrated in Fig. 3, is passing alongthe guideway I2. As previously stated, the carrier embodies bothelectroconductive and magnetic properties. As it passes through the coil51, its conductive body portion causes the resonator selector to respondand the relay 13, which is normally energized,releases its armature 14.The armature is pulled against its back contact 15 thereby supplyingcurrent to the armature 39 of relay 38. It will be remembered that meanshas been provided for maintaining the relay 13 in its deenergized stateuntil the carrier has passed the switch mechanism. The carriernextpasses between the pole pieces of the permanentmagnet l8 and immediatelythe magnetic selector mechanism is caused to function because of themagnetic material comprising the collar portion 18 of the carrier. Therelay 38 is thereby energized and its associated armature as is drawnagainst its front contact 4|. This now places current in the solenoidcircuit and the switch at point A is thrown over to deflect the carrierfrom the main tube l2 to the branch tube or outlet station. The circuitthen automatically returns to normal. It is obvious that the circuit asarranged will not permit selection at point A unless both the resonatorpick-up and the magnetic pick-up are excited, so that all carrierspossessing neither, or only one, of the plwsical properties mentionedwill continue past the point A.

Since one type of carrier has now been diverted from the guideway l2,only carriers having magnetic or electro-conductive properties orneither will approach point B. At this point is disposed a magneticpickup and all carriers having a magnetic collar will be selected, asexplained in connection with Fig. 1, for discharge at station B.

As the remaining carriers approach point C, the resonator selectorplaced at that point will cause all carriers having anelectro-conductive body to be discharged or switched from the mainguideway i2. Carriers made entirely of fibre or other material that isnon-magnetic and non-conduc tive will pass through the entire systemfrom the sending station to the remote end of the conveyor line.

From the above it will be seen that the system oi selective dischargeconstructed according to this invention may readily be applied topneumatic conveyer systems already in use with but slight change inapparatus. The carriers, in addition, are of substantially the samedimensions as those now in use and the latter may be easily andinexpensively adapted to be used with this invention.

Thus, I have provided a system of selective control for carrier conveyersystems which is not only less expensive to install and operate thansystems heretofore used, but which is less critical in its functioningand which does not necessitate the use of a grid controlled rectifier orcomplicated timing mechanism.

While this invention has been shown'in but three forms, it will beobvious to those skilled in the art that it is not so limited but issusceptible to various other changes and modifications without departingfrom the spirit thereof, and it is desired therefore, that only suchlimitations shall be placed thereon as are imposed by the prior art oras specifically set forth in the appended claims.

What is claimed is:

1. In a conveyer system comprising, a guideway embodying a branch outletand deflector means, carriers adapted to travel in said system andembodying conductive bodies having predetermined degrees of permeance, avalve provided with a cathode, anode and grid to control said deflectormeans and thereby control the path 01 said carriers, means for normallymaintaining the potential of said grid substantially at the potential ofsaid cathode, means responsive to the passage of said carriers toincrease the negative potential of said grid, and energy storage meansin circuit with said grid to sustain said increased grid potential for apredetermined time not less than the time required for the passage ofsaid carrier from the responsive means to the deflector means.

2. In a conveyer system embodying selective routing, the combination ofa main guideway having three branch outlets therefrom each having adeflector for diverting predetermined carriers from said guideway intosaid branch outlets, four types of carriers adapted to travel throughsaid system, the first embodying both magnetic and electro-conductiveproperties, the second embodying magnetic properties, the thirdembodying electro-conductive properties, and the fourth embodyingneither of the aforementioned properties, a grid controlled valveassociated with each of said outlets and having an output circuit tocontrol said deflector, means associated with each of said outletsdisposed in advance thereoi along said main guideway to control thepotential of the grid of said valve and thereby alter its impedance, themeans for said first outlet being responsive only to carriers havingboth magnetic and electro-conductive properties, said second outletmeans responsive only to carriers having magnetic properties and saidthird outlet means responsive only to carriers having electro-con-'ductive properties, carriers having neither of said properties beingpermitted to continue uninterruptedly along said main guideway andresistance shunted condensers in said grid circuits to prolong thealtered impedance conditions of said valves.

3. In a conveyer system embodying selective routing, the combination ofa. main guideway having three branch outlets therefrom each having adiverting deflector, a grid controlled valve associated with each ofsaid outlets and having an output circuit to control said deflector,means associated with each of said outlets and disposed in advancethereof adjacent to said main guideway to control the potential of thegrid of said valve and thereby alter its impedance, the means for saidfirst outlet including a selector responsive to both magnetic andelectro-conductive influences, the second outlet means including aselector responsive only to magnetic influences, and said third outletmeans including a selector responsive only to electro-conductiveinfluences.

4. In a conveyer system, comprising a guideway embodying a. branchoutlet and deflector means, carriers adapted to travel in said systemand embodying conductive bodies having predetermined degrees ofpermeance, a valve provided with a cathode, anode and grid to controlsaid deflector means and thereby control the path of said carriers,means for normally maintaining the potential of said grid substantiallyat the potential of said cathode, selector means including a magnet withits field embracing a section of said guideway, said selector meansbeing responsive to way embodying a branch outlet and deflector means,carriers adapted to travel in said system and embodying conductivebodies having predetermined degrees of permeance, a valve provided witha cathode, anode and grid to control said deflector means and therebycontrol the path of said carriers, means for normally maintaining thepotential or said grid substantially at the potential of said cathode,selector means including a resonator .coil with its convolutionsenveloping a section of said guideway, said selector means beingresponsive to the passage of said carriers to increase the negativepotential, of said grid,

and energy storage means in circuit with said rid to sustain saidincreased grid potential for a predetermined time slightly in excess ofthe time required for the passage of the carrier from the selector meansto the deflector means.

WILLIAM HARGREAVEB.

